1. Field of the Invention
The present invention relates to a magnetic recording apparatus for reading and writing data such as numeric data and image information and which is suitable to be used as a peripheral device of a computer.
2. Description of the Related Art
The magnetic recording apparatus comprises a magnetic disk, a head slider for writing information on the recording surface of the magnetic disk and reading the information, a carriage having an arm thereon for holding the head slider, and an actuator for driving the carriage. Since the gap between the disk and the head slider is slight, there is a great possibility that the disk surface or the head slider will be damaged when they contact each other when a shock or a vibration is applied to the magnetic recording apparatus. It is important to protect the disk surface from damage so that the disk is capable of carrying out a favorable recording.
Conventionally, the head slider is floated over the disk by utilizing positive pressure of an air flow generated by the rotation of the disk, with a slight gap held between the head slider and the disk surface. This type of head slider is urged toward the disk surface by a flexure supporting the head slider elastically. While the disk is rotating, the head slider is floating over the disk with a certain gap provided therebetween due to air bearing effect generated by the air flow. Air bearing effect is not generated when the disk is not rotating. In consideration of this, a landing zone which is a non-recording region is provided on the disk surface so that the head slider does not contact the recording surface of the disk. Thus, the head slider rests on the landing zone when the disk is not rotating. This system is called a contact start/stop system.
According to this system, there is a possibility that the head slider will move out of the landing zone when a shock or a vibration is applied to the apparatus and will damage the recording surface of the disk or the head slider. In order to solve this problem, the head slider is locked in the landing zone when the disk is not rotating and unlocked upon start of the rotation of the disk.
A conventional magnetic recording apparatus empoloying the above-described system is shown in FIGS. 19 and 20. The disks of a plurality of disks 32 are spaced from each other at regular intervals. A flexure 24 serving as an elastic member supports a head slider 23 mounted on the leading end of an arm corresponding to each surface of each disk and mounted on a carriage 25 and scanning the recording surface of the disk 32, with a certain interval provided between the disk 32 and the head slider 23. Upon the rotation of the disk 32, the carriage 25 is driven by an actuator 30 so that the carriage 25 swings about a shaft 27 in the radial direction of the disk 32. Thus, the head slider 23 on each arm on the carriage scans the entire recording region of the disk 32.
When the disk is not rotating, the elastic force of the flexure 24 keeps the head slider 23 in contact with a landing zone 31 provided in an inner zone of the disk 32. During the rotation of the disk 32, the head slider 23 is subjected to an air flow generated by the rotation of the disk 32, thus floating under positive pressure. Then, because of the air bearing effect, the head slider 23 scans the disk surface with a slight gap kept between the disk surface and the head slider 23.
When the disk 32 is not rotating, the air bearing effect is not generated. Therefore, the head slider 23 rests on the landing zone 31 which is a non-recording region so that the head slider 23 is not brought into contact with the recording surface of the disk 32.
According to the carriage locking device of the magnetic recording apparatus of the above construction, an airvane 21 for unlocking the carriage 25 is rotatably supported by a shaft 28, and vanes are provided which extend from the shaft 28 over and below each disk 32. One end of a safety latch 22 is rotatably mounted on the shaft 28 so that the latch 22 rotates about the shaft 28 interlocking with the pivotal motion of the airvane 21.
With the disks 32 stopped, the latch 22 rotates in the direction, in which the urging force of the spring 26 is applied, interlocking with the airvane 21 which is urged to pivot toward the carriage 25 by the spring 26. As a result, the latch 22 contacts a carriage fixing pin 29 provided on the carriage 25, thus preventing the carriage 25 from swinging in the radial direction of the disk 32, namely, toward the periphery of the disk 32. Thus, the head slider 23 mounted at the leading end of each arm on the carriage 25 is prevented from swinging from the landing zone 31 toward the periphery of the disk 32.
With the start of the rotation of the disk 32, an air flow is generated. The air flow acts on the airvane 21, thus rotating the airvane 21 against the urging force of the spring 26. Then, the latch 22 interlocked therewith rotates, thus disengaging from the fixing pin 29. As a result, the carriage 24 is unlocked from the latch 22. Then, the actuator 30 drives the carriage 25, with the result that the head slider 23 mounted on the leading end of each arm on the carriage 25 swings radially from the landing zone 31 to the recording region of the disk 32.
Upon stopping of the disk 32, the carriage 25 pivots, thus moving the head slider 23 on each arm to the landing zone 31. At this time, the airvane 21 returns to the stop position by the urging force of the spring 26 because the air flow is not generated when the disk 32 is not rotating. Consequently, the latch 22 contacts the fixing pin 29. As a result, the head slider 23 is locked in the landing zone 31.
In order to meet the demand for the development of a mass storage magnetic recording apparatus for storing an increased amount of information, it is necessary to increase the recording density and recording area of the disk. In order to increase the recording density, it is necessary to float the head slider a small distance above or below the disk surface. In order to increase the recording area, it is necessary to reduce the area of the non-recording region, for example, the landing zone of the carriage.
As described above, the above head slider is floated over the disk surface by positive pressure. The problem with the above conventional apparatus is that the gap between head slider and the disk surface cannot be reduced to less than a certain amount and the landing zone needs to be provided on the disk so that the head slider rests on the disk surface when the disk is not rotating. Thus, the apparatus is incapable of meeting the abovedescribed demand.
In order to solve the above problem, the following construction seems preferable. That is, the flexure always keeps the head slider out of contact with the disk surface, and in addition, an air flow generated by the rotation of the disk is applied to the region between a recess section formed on the bottom surface of the head slider and the disk so as to generate negative pressure in the region, for example, which is disclosed in U.S. Pat. No. 3,855,625. The head slider is drawn toward the disk surface by negative pressure sucking force. This construction allows the head slider to float above or below the disk with a small distance between the head slider and the disk surface even when the disk is rotating. Therefore, it is unnecessary to form the landing zone for the head slider. Hence, the apparatus is capable of processing a great amount of information.
The above-described head slider is elastically supported over the disk surface with a slight interval held therebetween when the disk is not in operation. The head slider is easily moved vertically when a shock or a vibration is applied to the apparatus. That is, there is a great possibility that the head slider will be brought into contact with the disk recording surface and damage the disk or the head slider. With to the above-described latch for regulating the movement of the carriage, the vertical movement of the head slider cannot be suppressed. Therefore, the head slider may damage the disk.